An avian 40 KDa nucleoprotein binds preferentially to a promoter sequence containing one single pair of methylated CpG.
An avian 40 KDa nucleoprotein binds preferentially to a promoter sequence containing one single pair of methylated CpG.
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禽类 40 KDa 核蛋白优先结合包含一对甲基化 CpG 的启动子序列。
DOI：
10.1093/nar/19.5.1029
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发表时间：
1991
影响因子：
14.9
通讯作者：
Jean
中科院分区：
文献类型：
--
作者：
André Pawlak;Margaret Bryans;Jean
与寡核苷酸的体外转录竞争已经表明，下调因子可以被覆盖禽卵黄蛋白原II基因启动子的特定区域的甲基化寡核苷酸置换（Proc.Natl.Acad.Sci. Acad. Sci USA，（1990）87，3047-3051）。凝胶迁移率变化和竞争分析表明，优先结合甲基化DNA（MDBP-2）的蛋白质是存在于分馏母鸡和公鸡核提取物。该蛋白质与卵黄蛋白原II启动子的甲基化序列5 ′ TTCACCTTmCGCTATG-AGGGGGATCATACTGG ′ 3 ′（核苷酸位置+2至+32）结合，而不与其它甲基化DNA序列结合。通过部分脱嘌呤和脱嘧啶寡核苷酸的DNA结合干扰实验研究了MDBP-2与DNA的接触点。该蛋白质的分子量约为40 KDa，主要存在于肝脏和输卵管中。从公鸡和母鸡肝核提取物的MDBP-2的蛋白水解剪切带移测定表明，从两个来源的蛋白质是不同的。体外转录实验表明，添加含有纯化核组分的添加物以纯化核依赖的方式转录卵黄蛋白原II基因。
In vitro transcription competition with oligonucleotides has shown that a down regulating factor can be displaced by a methylated oligonucleotide covering a specific region of the avian vitellogenin II gene promoter (Proc. Natl. Acad. Sci USA, (1990) 87, 3047-3051). Gel mobility shift and competition assays show that a protein binding preferentially to methylated DNA (MDBP-2) is present in fractionated hen and rooster nuclear extracts. The protein(s) bind to the methylated sequence 5' TTCACCTTmCGCTATG-AGGGGGATCATACTGG' 3' (nucleotide positions +2 to +32) of the vitellogenin II promoter and not to other methylated DNA sequences. Contact points of the MDBP-2 with DNA were studied by DNA binding interference experiments with partially depurinated and depyrimidinated oligonucleotides. The protein has an approximate molecular weight of 40 KDa and is mainly found in the liver and oviduct. Proteolytic clipping bandshift assays of the MDBP-2 from rooster and hen liver nuclear extracts indicate that the protein from the two sources are different. In vitro transcription experiments show that the addition of a purified nuclear fraction containing the addition of a purified nuclear dependent manner the transcription of vitellogenin II gene.